The present disclosure relates to a semiconductor integrated circuit including a power supply switch circuit having a function of switching power supply voltages to be supplied.
In general, a signal frequency is increased in a high-speed interface, and thus, the voltage level of a signal is reduced to reduce an increase in power consumption. For example, while secure digital (SD) cards that comply with the traditional interface standard use a 3.3-V signal interface, SD cards that comply with the state-of-the-art high-speed standard use a 1.8-V signal interface. In the case of interface standards widely accepted such as the Secure Digital standard, devices are required to support both new and old standards, and therefore, interface circuits need to switch signal voltage levels, depending on the standard with which a connected SD card complies. Therefore, a power supply switch circuit is needed which switches power supply voltages, which are to be supplied to the interface circuit, between 3.3 V and 1.8 V.
One conventional technique provides a power supply switch circuit which does not cause an unwanted current, such as the parasitic diode current, even when any of a plurality of power supply voltages is in off-state (see WO2014/038115).